Terahertz spectrum quantum weak measurement method, system and application

Abstract

The application provides a terahertz spectrum quantum weak measurement method, a system and application, belongs to the technical field of terahertz, and the terahertz spectrum quantum weak measurement method is applied to a terahertz spectrum quantum weak measurement system; the system comprises a first polarizer, a second polarizer, a terahertz time-domain spectrum unit, a transmitting end, a detecting end and a sample carrier; the terahertz quantum weak measurement method and system based on quantum weak value amplification effect can break through the trace detection limit of the current terahertz technology. According to the application, a terahertz polarization state (pre-selected state) is selected, a small change of a measured quantity produces a kind of'micro' disturbance, a strong measurement is used to project the disturbed system state to a post-selected state, and then a terahertz quantum weak measurement system is established; most chiral drugs have resonance absorption in the terahertz wave band, which is beneficial to using the small change of optical rotation of chiral molecules as weak coupling to realize high-sensitivity conformation identification of chiral drugs.

Description

Technical Field

[0001] This invention relates to the field of terahertz technology, and in particular to terahertz spectroscopy quantum weak measurement methods, systems and applications. Background Technology

[0002] The study of drug chirality is crucial in biomedical fields such as drug design and synthesis, and protein structure determination, and is directly related to human health. Many chiral drugs exhibit drastically different pharmacological, toxicological, and pharmacokinetic characteristics when interacting with proteins in organisms. Therefore, identifying and testing drug chirality is imperative and extremely important.

[0003] Currently, commonly used methods for identifying chiral molecules mainly include: chromatography (high performance liquid chromatography, gas chromatography, supercritical fluid chromatography), capillary electrophoresis (capillary zone electrophoresis, capillary electrochromatography), and spectrometry (circular dichroism spectroscopy, Raman spectroscopy). These methods all suffer from one or more of the following drawbacks: cumbersome operation, destructive testing, reliance on standards, strong limitations, and high detection limits, making them less than ideal methods. Compared to other wavelengths such as visible light, terahertz (THz, frequency 0.1-10THz) electromagnetic waves exhibit strong sensitivity and fingerprinting properties for low-frequency molecular vibrations. Terahertz technology, as a non-contact, label-free, and non-ionizing detection method, possesses effective detection capabilities for molecular conformation and weak interactions, demonstrating strong detection advantages and application potential in chiral molecule conformation recognition. However, currently used terahertz time-domain spectroscopy techniques are mostly limited to spectroscopic testing and qualitative analysis, making quantitative detection difficult, and their sensitivity falls far short of requirements.

[0004] Therefore, a terahertz spectroscopy quantum weak measurement technique and system is established. By utilizing the characteristic fingerprint of the terahertz wave band matching the energy level spacing caused by macromolecular vibration, rotation, and conformational changes, and the high sensitivity of quantum weak measurement to amplify the signal without amplifying technical noise, the detection sensitivity of chiral molecules is greatly improved, meeting the need for high-sensitivity conformational recognition of chiral drugs. Summary of the Invention

[0005] To address the shortcomings of insufficient measurement sensitivity in current chiral samples, this invention proposes a terahertz spectroscopy quantum weak measurement method, system, and application.

[0006] The technical solution adopted in this invention is:

[0007] A terahertz spectral quantum weak measurement method is applied to a terahertz spectral quantum weak measurement system. The system includes a first polarizer, a second polarizer, a terahertz time-domain spectral unit, a transmitter, a detector, a sample carrier, and a terahertz spectral quantum weak measurement calculation unit. The method includes:

[0008] Preselection refers to the polarization state of the incident terahertz wave emitted by the terahertz time-domain spectral unit through the transmitter, which is selected by the first polarizer as the quantum preselected state;

[0009] The polarization state selected by the second polarizer is taken as the quantum post-selected state.

[0010] Before measurement, the quantum pre-selected state and the quantum post-selected state are orthogonal to each other;

[0011] With weak coupling, the sample to be tested is placed between the first polarizer and the second polarizer. After the terahertz wave interacts with the sample to be tested, the terahertz wave spectrum is received by the terahertz time-domain spectral unit through the detector end and then measured.

[0012] A quantum weak measurement model for terahertz spectroscopy was constructed, and the value β, which is the change in polarization state of the terahertz wave caused by the interaction between the terahertz wave and the sample under test, was selected after calculation.

[0013] The change in polarization state β of the terahertz wave reflects the quantifiable X of the sample under test.

[0014] In its operation, this application creatively employs a selected terahertz polarization state (quantum pre-selected state). The minute change in the measured quantity generates a "micro" perturbation on the polarization state of the terahertz wave. The perturbation quantity is then projected onto the quantum post-selected state using a strong measurement method, thereby establishing a terahertz quantum weak measurement system.

[0015] Preferably, the measurand X ∝ β, and the measurand X can be calculated from β through calibration; this facilitates the quantitative calculation of the measurand X and helps to improve measurement accuracy and sensitivity.

[0016] Preferably, when the terahertz wave interacts with the sample under test, the quantum preselected state is at an angle to the X direction. π / 4, the quantum post-selection state is at an angle to the X direction. 3π / 4-β; utilizing currently mature π / 4 及3π The / 4 polarization state facilitates measurement and debugging, and helps improve measurement accuracy and sensitivity.

[0017] Preferably, the terahertz spectral quantum weak measurement model is as follows:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] Among them, A w The quantum weak value is β, where β is the polarization state change of the terahertz wave, and ImA is the value of the quantum weak value. w For A w The imaginary part of the terahertz wave; G0 is the coupling strength between the terahertz wave and the sample under test; p is the photon momentum of the terahertz wave; δp is the change in photon momentum of the terahertz wave; δλ is the wavelength shift of the terahertz wave; λ0 corresponds to the photon momentum p0, and Δλ is the spectral width.

[0027] Preferably, the interaction between the terahertz wave and the sample under test adopts a transmission mode or a metal grating-refractive mode, which facilitates the weak coupling of the terahertz wave with respect to optical rotation (degree) and refractive index.

[0028] Preferably, when in transmission mode, the sample carrier is the sample cell, and the metric X of the sample to be tested is the optical rotation b.

[0029] Preferably, when in metal grating-refractive mode, the sample carrier is a prism coated with a metal grating, and the quantifiable X of the sample to be tested is the refractive index c.

[0030] The present invention also provides a terahertz spectral quantum weak measurement system, comprising,

[0031] The first polarizer is positioned at the terahertz wave incident end of the terahertz time-domain spectral unit to select the terahertz wave in the quantum preselected state.

[0032] The test carrier is positioned between the first polarizer and the second polarizer to enable weak coupling between the quantum preselected state terahertz wave and the test sample on the test carrier.

[0033] The second polarizer is configured at the terahertz wave detector of the terahertz time-domain spectral unit to select the terahertz wave of the quantum post-selected state; before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other;

[0034] The terahertz time-domain spectral unit is configured to emit, modulate, detect, and spectroscopically measure terahertz waves.

[0035] The terahertz spectral quantum weak measurement calculation unit is configured to select the polarization state change value of the terahertz wave and the measurement of the sample after calculating the terahertz wave polarization state change value and the sample to be measured based on the terahertz spectral quantum weak measurement model and the terahertz wave spectrum.

[0036] Preferably, the system further includes;

[0037] A half-wave plate and a first focusing lens are positioned between the terahertz wave incident end and the first polarizer to adjust the intensity of the incident terahertz wave.

[0038] And a second focusing lens is configured between the second polarizer and the terahertz wave detection end for focusing detection.

[0039] Preferably, the test carrier is a sample cell or a prism coated with a metal grating.

[0040] This invention also proposes the application of the above-mentioned terahertz spectroscopy quantum weak measurement system in the highly sensitive detection of chiral drugs.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The terahertz quantum weak measurement technique based on the quantum weak value amplification effect proposed in this invention can break through the trace detection limit of current terahertz technology. A terahertz polarization state (pre-selected state) is selected, and a tiny change in the measured state produces a "micro" perturbation. A strong measurement is then used to project the perturbed system state onto the post-selected state, thereby establishing a terahertz quantum weak measurement system. Most chiral drugs exhibit resonant absorption in the terahertz band, which is beneficial for utilizing the micro-changes in the optical rotation of chiral molecules as a weak coupling effect to achieve highly sensitive conformational recognition of chiral drugs.

[0043] 2. Establish the theoretical foundation of terahertz quantum weak measurement, namely the transfer function model of terahertz quantum weak value amplification effect, which is the foundation and support for terahertz spectral quantum weak measurement technology and system.

[0044] 3. By integrating terahertz time-domain spectroscopy and quantum weak measurement techniques, a quantum weak measurement system is constructed on the terahertz time-domain spectroscopy system. The establishment of transmission mode and metal grating-refractive mode can significantly improve the detection accuracy of optical rotation and refractive index of substances, and develop a new label-free terahertz trace detection technology.

[0045] 4. The terahertz quantum weak measurement technology and system involved in this invention are expected to improve the measurement sensitivity by 2-3 orders of magnitude compared with the commonly used terahertz time-domain spectroscopy technology. Attached Figure Description

[0046] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0047] Figure 1 This is a block diagram of a terahertz spectral quantum weak measurement system;

[0048] Figure 2 This is a flowchart of the terahertz spectroscopy quantum weak measurement method;

[0049] Figure 3 This is a schematic diagram of the terahertz quantum weak value amplification effect mechanism;

[0050] Figure 4 The terahertz spectral quantum weak measurement system is in transmission mode;

[0051] Figure 5 The terahertz spectral quantum weak measurement system is in the metal grating-refractive mode;

[0052] Figure 6 This is a graph showing the terahertz quantum weak measurement results of the terahertz spectroscopy quantum weak measurement system in a low-concentration glucose sample. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0054] The study of drug chirality is crucial in biomedical fields such as drug design and synthesis, and protein structure determination, and is directly related to human health. Many chiral drugs exhibit drastically different pharmacological, toxicological, and pharmacokinetic characteristics when interacting with proteins in organisms. Therefore, identifying and testing drug chirality is imperative and extremely important.

[0055] Currently, commonly used methods for identifying chiral molecules mainly include: chromatography (high performance liquid chromatography, gas chromatography, supercritical fluid chromatography), capillary electrophoresis (capillary zone electrophoresis, capillary electrochromatography), and spectrometry (circular dichroism spectroscopy, Raman spectroscopy). These methods all suffer from one or more of the following drawbacks: cumbersome operation, destructive testing, reliance on standards, strong limitations, and high detection limits, making them less than ideal methods. Compared to other wavelengths such as visible light, terahertz (THz, frequency 0.1-10THz) electromagnetic waves exhibit strong sensitivity and fingerprinting properties for low-frequency molecular vibrations. Terahertz technology, as a non-contact, label-free, and non-ionizing detection method, possesses effective detection capabilities for molecular conformation and weak interactions, demonstrating strong detection advantages and application potential in chiral molecule conformation recognition. However, currently used terahertz time-domain spectroscopy techniques are mostly limited to spectroscopic testing and qualitative analysis, making quantitative detection difficult, and their sensitivity falls far short of requirements.

[0056] Therefore, this application discloses a terahertz spectral quantum weak measurement method and system.

[0057] Please see Figure 1-6The system 100 includes a terahertz time-domain spectral unit 101, which is configured for terahertz time-domain spectral analysis.

[0058] Transmitter 102 is configured to emit incident terahertz waves;

[0059] Detector 103 is configured to receive terahertz waves;

[0060] The first polarizer 104 is configured as a pre-selector, through which the terahertz wave is selected to a quantum pre-selected state;

[0061] The second polarizer 105 is configured as a post-selector, through which the terahertz wave is selected to obtain a quantum post-selected state.

[0062] Furthermore, before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other;

[0063] The sample carrier 106 is configured to carry the sample to be tested 10 between the first polarizer 104 and the second polarizer 105, thereby completing the weak coupling between the quantum preselected state terahertz wave and the sample to be tested.

[0064] The terahertz spectral quantum weak measurement calculation unit 1011 is configured to select the polarization state change value of the terahertz wave and the measurement of the sample to be measured after calculating the terahertz wave polarization state change value and the terahertz wave spectrum based on the terahertz spectral quantum weak measurement model and the terahertz wave spectrum.

[0065] A terahertz spectral quantum weak measurement method is applied to the aforementioned terahertz spectral quantum weak measurement system. The method includes: S1, pre-selection, where the polarization state of the incident terahertz wave emitted by the terahertz time-domain spectral unit through the transmitter is selected by a first polarizer as the quantum pre-selected state; post-selection, where the polarization state of the terahertz wave is selected by a second polarizer as the quantum post-selected state; before measurement, the quantum pre-selected state and the quantum post-selected state are orthogonal to each other;

[0066] S2, Weak Coupling and Spectral Measurement: The sample to be tested is placed between the first polarizer and the second polarizer. After the terahertz wave interacts with the sample to be tested, the terahertz wave spectrum is received by the terahertz time-domain spectral unit through the detector end and then measured.

[0067] S3. Construct a quantum weak measurement model for terahertz spectroscopy, and select the value β of the terahertz wave polarization state change caused by the interaction between the terahertz wave and the sample under test after calculation.

[0068] S4. The terahertz wave polarization state change value β reflects the quantifiable X of the sample under test.

[0069] In some embodiments, when the terahertz wave interacts with the sample under test, the quantum preselected state is at an angle to the X direction. π A terahertz wave of / 4, in its quantum post-selected state, is at an angle to the X direction. 3π / 4-β; utilizing currently matureπ / 4 and 3π The / 4 polarization state facilitates measurement and debugging, and helps improve measurement accuracy and sensitivity.

[0070] In some embodiments, the quantum preselected state is a terahertz wave at an angle θ to the X direction, and the quantum postselected state is at an angle θ to the X direction. Where θ takes values In this embodiment, the terahertz quantum weak amplification effect mechanism is as follows: using a terahertz photonic system as the analyte subsystem, selecting the polarization state of the terahertz photon as the analyte physical quantity and the momentum of the terahertz photon as the pointer; its weak coupling effect refers to the weak absorption, scattering, dispersion, or polarization rotation of the analyte molecule when the terahertz wave propagates in the sample; the terahertz spectral changes (broadening, frequency shift, etc.) can be characterized by the filtered post-selected state and finally measured by a terahertz detector (balanced detector, spectrometer, power meter, etc.);

[0071] In this embodiment, the terahertz frequency domain transfer function model for quantum weak amplification is as follows: mutually perpendicular terahertz wave polarization states are selected as mutually orthogonal quantum preselected states |ψ pre >and quantum post-selection state|ψ post >; The optical rotation of chiral molecules causes a rotation of the polarization state of terahertz waves, i.e., weak coupling. The weakly coupled polarization state is represented as |ψ'>; then the weak value is

[0072]

[0073] In quantum weak measurement, the absolute value of the weak value is the amplification factor of the measured physical quantity; as can be seen from formula (1), when the current selected state and the subsequent selected state are nearly orthogonal, this factor can be much greater than 1. Therefore, based on the current selected state, the subsequent selected state, and the weak coupling process, according to the terahertz emission wave expression and the detection mechanism, and according to the quantum weak measurement operator... Criteria, derivation of weak value expressions and frequency domain transfer function models;

[0074] In this embodiment, the preferred approach is to establish the terahertz quantum weak value amplification effect mechanism: such as Figure 3 The Hamiltonian operator for the quantum weak interaction is defined as follows: Where g(t) is the coupling strength, which can be considered a constant inside the sample and zero outside the sample, and It is determined by the sample thickness L, the absorption coefficient α(ω), and the effective refractive index n(ω); It is the momentum operator of terahertz photons in the Z direction; It is the polarization operator for terahertz photons, and |H> and |V> are The two eigenstates of have eigenvalues ​​of ±1, i.e. respectively represent the polarization states in the X and Y directions. Select the terahertz polarized light at an angle of π / 4 with the X direction as the preselected state of terahertz photons, and the terahertz polarization state at an angle of 3π / 4 - β (β << 1, which is the polarization state change caused by the transmission of terahertz waves in the measured object) as the postselected state. Then

[0075]

[0076] the weak value is obtained therefrom

[0077]

[0078] Because it is a weak coupling effect and β << 1, so is a very large amplification factor.

[0079] Secondly: the terahertz frequency-domain transfer function model for quantum weak value amplification; the coupling strength between the terahertz wave and the measured object is where x = νt (0 < x < L), ν is the propagation speed of the terahertz wave in the measured object, and L is the thickness of the measured object. When the terahertz wave has advanced x part in the sample, there is still L - x part that has not been passed through; let be the change amount per unit thickness in the sample, then The weak value is obtained through derivation as

[0080]

[0081] where the photon momentum h is the Planck constant, λ is the terahertz wavelength, v is the terahertz frequency, and c is the propagation speed of the terahertz wave in vacuum.

[0082] For G0p << 1 and β << 1

[0083]

[0084] its imaginary part

[0085]

[0086] Compared with the extinction coefficient of the near-infrared optical polarizer, the extinction coefficient of the terahertz polarizer is poor, resulting in a large error in the postselection of terahertz quantum weak measurement. Therefore, the imaginary part of the frequency-domain quantum weak measurement formula is preferably used as the weak value amplification part. From this, the change amount of the terahertz photon momentum p caused by the interaction is

[0087]

[0088] From this, the wavelength shift amount is obtained as

[0089]

[0090] Here, the central wavelength λ0 corresponds to the photon momentum. Δλ is the spectral width.

[0091] Therefore, the frequency shift of the measured terahertz spectrum can be used to derive the tiny change β in the polarization state of the terahertz wave after passing through the sample, and the value of β is determined by the tiny measurand in the sample.

[0092] In some embodiments, the terahertz time-domain spectral unit 101 is connected between the transmitter 102 and the detector 103 to form a basic terahertz time-domain spectral system. The terahertz time-domain spectral unit 101 specifically includes a femtosecond laser, a delay control, a photoconductive switch, an antenna, an electro-optic crystal, a Wollaston prism, and a balanced detector, etc.

[0093] The transmitter 102 and the detector 103 share a terahertz wave transmission axis a. A terahertz half-wave plate 231, a first focusing lens 232, and a first polarizer 104 are arranged along axis a between the transmitter 102 and the detector 103 to perform pre-selection for terahertz quantum weak measurement.

[0094] The half-wave plate 231 is used to adjust the intensity of terahertz light, and the first focusing lens 232 is used to focus the terahertz wave.

[0095] The second polarizer 105 is disposed along axis a between the first polarizer 104 and the detector end 103; it is configured as the post-selection for terahertz quantum weak measurement.

[0096] A second focusing lens 233 is disposed on axis a between the second polarizer 105 and the detector 103. It is used to focus the terahertz wave filtered out by the second polarizer and make it enter the detector 103. The terahertz wave entering the detector enters the electro-optic crystal, Wollaston prism and balanced detector in the basic terahertz time-domain spectroscopy system, and completes the spectral measurement using electro-optic sampling technology.

[0097] The sample carrier 106 is positioned between the first polarizer 104 and the second polarizer 105 to carry the sample to be tested 10, so that the terahertz wave is weakly coupled to the sample to be tested.

[0098] Please see Figure 4 In some embodiments, the sample to be tested is a chiral molecule, and the quantified X is the optical rotation b of the chiral molecule to be detected. In this case, the terahertz wave interacts with the sample to be tested in transmission mode.

[0099] The sample carrier 106 is a sample cell 1061, and the sample to be tested 10 is placed in the sample cell 1061.

[0100] The terahertz wave of the quantum preselected state enters from one side of the sample cell 1061 and is filtered out from the other side; the sample to be tested in the sample cell is weakly coupled with the terahertz wave of the quantum preselected state.

[0101] Please see Figure 5 In some embodiments, the sample to be tested is a chiral molecule, and the measured value X is the refractive index c of the chiral molecule. In this case, the interaction between the terahertz wave and the sample to be tested adopts the metal grating-refractive mode. The sample carrier 106 is a prism 1062 coated with a metal grating. In the metal grating-refractive mode, when the quantum preselected state terahertz wave is incident on the metal grating at any angle (determined by the position of the prism coated with the metal grating and the structure of the metal grating), the small change in the refractive index of the sample to be tested will cause a change in the polarization state of the terahertz wave parallel to the metal grating, while the polarization state of the terahertz wave perpendicular to the metal grating is unaffected. Therefore, a small change in the phase difference is generated between the two, completing the quantum weak coupling effect.

[0102] The terahertz wave in the quantum preselected state is weakly coupled with the sample under test. The quantum postselected state of the terahertz wave filtered out by the second polarizer 105 is 3π / 4-β; β is the change in polarization state of the terahertz wave caused by the interaction between the terahertz wave and the sample under test.

[0103] Therefore, by measuring the frequency shift of the terahertz spectrum, the terahertz spectral quantum weak measurement calculation unit 1011 can derive the minute change β of the polarization state of the terahertz wave after passing through the sample from the above equations (1)-(8). In some embodiments, the measurement X can be calculated by calibrating it with X∝β.

[0104] In some embodiments, the terahertz spectral quantum weak measurement calculation unit 1011 is built into the terahertz time-domain spectral unit 101; in some embodiments, the terahertz spectral quantum weak measurement calculation unit 1011 is connected to the terahertz time-domain spectral unit 101 via wired and / or wireless communication.

[0105] In some embodiments, using ultrapure water as a solvent, low-concentration glucose solutions ranging from 0.01 mg / ml to 0.10 mg / ml were prepared, with a concentration gradient of 0.01 mg / ml. 60 μL of each solution was dropped onto a double-sided polished JGS1 quartz plate with a diameter of 12 mm and a thickness of 1 mm. After air drying, a biofilm morphology was formed. Terahertz signal testing was performed using the above system, and the results are as follows... Figure 6As shown in the figure, the red line represents the test curve combining the quantum weak measurement principle and terahertz time-domain spectroscopy. It shows that as the sample concentration increases, the peak-to-peak ratio of the time-domain signal (peak-to-peak value of the transmission time-domain signal of the test sample / peak-to-peak value of the transmission time-domain signal of the reference sample) gradually decreases. This is because as the number of glucose molecules gradually increases, their absorption of terahertz waves gradually increases; this demonstrates the high sensitivity of this technique in detecting low concentrations. The blue line represents the test curve based on traditional terahertz time-domain spectroscopy. Its trend remains almost unchanged with increasing sample concentration, indicating that this concentration range exceeds the detection limit of traditional terahertz time-domain spectroscopy. These results verify the effectiveness and high sensitivity of the terahertz spectroscopy quantum weak measurement technique and system.

[0106] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method of terahertz spectroscopic quantum weak measurement, characterized by, An application is made to a terahertz spectral quantum weak measurement system, the system comprising a first polarizer, a second polarizer, a terahertz time-domain spectral unit, a transmitter, a detector, a sample carrier, and a terahertz spectral quantum weak measurement calculation unit, the method comprising: Pre-selection: The first polarizer selects the polarization state of the terahertz wave as the quantum pre-selected state; The second polarizer selects the polarization state of the terahertz wave as the quantum post-selection state. Before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other; Weak coupling and spectral measurement: The terahertz wave is weakly coupled with the sample on the sample carrier and then received by the detector. The terahertz wave spectrum is then measured by the terahertz time-domain spectral unit. A quantum weak measurement model for terahertz spectroscopy was constructed, and the polarization state change value of the mid-terahertz wave was selected after calculation. The change in the polarization state of the terahertz wave reflects the measurement to be performed on the sample. The quantum pre-selection state of the terahertz wave is in the direction of X when the terahertz wave is weakly coupled with the sample to be measured The quantum post-selection state of the terahertz wave is in the direction of X , is a change value of the polarization state of the terahertz wave in the post-selection. Terahertz spectroscopy quantum weak measurement model: wherein, is a quantum weak value, β is a change value of a polarization state of a terahertz wave, is an imaginary part of is a coupling strength of a terahertz wave with a measured sample; is a photon momentum of a terahertz wave; is a change amount of the photon momentum of the terahertz wave; is a wavelength shift amount of the terahertz wave; corresponds to the photon momentum , is a spectral width.

2. The terahertz spectral quantum weak measurement method according to claim 1, characterized in that, The weak coupling between the terahertz wave and the sample under test is achieved through either transmission mode or metal grating-refractive mode.

3. The terahertz spectral quantum weak measurement method according to claim 2, characterized in that, When in transmission mode, the sample carrier is the sample cell, and the metric to be measured on the sample is optical rotation.

4. The terahertz spectral quantum weak measurement method according to claim 2, characterized in that, When in metal grating-refractive mode, the sample carrier is a prism coated with a metal grating, and the metric to be measured on the sample is the refractive index.

5. A terahertz spectral quantum weak measurement system, characterized in that, Using the measurement method as described in any one of claims 1-4, the system comprises: The first polarizer, used for pre-selection, is configured at the terahertz wave incident end of the terahertz time-domain spectral unit to select the quantum pre-selected state of the terahertz wave. The sample carrier, used to hold the sample to be measured, is positioned between the first polarizer and the second polarizer to ensure weak coupling between the terahertz wave and the sample to be measured on the sample carrier during measurement. The second polarizer, used for post-selection, is configured at the terahertz wave detector end of the terahertz time-domain spectral unit to select the quantum post-selected state of the terahertz wave; before measurement, the quantum post-selected state and the quantum pre-selected state are orthogonal to each other; The terahertz time-domain spectral unit is configured to emit, modulate, detect, and spectroscopically measure terahertz waves. The terahertz spectral quantum weak measurement calculation unit is configured to select the polarization state change value of the terahertz wave and the measurement of the sample after calculating the terahertz wave polarization state change value and the sample to be measured based on the terahertz spectral quantum weak measurement model and the terahertz wave spectrum.

6. A terahertz spectral quantum weak measurement system according to claim 5, characterized in that, The system also includes; A half-wave plate and a first focusing lens are positioned between the terahertz wave incident end and the first polarizer to adjust the intensity of the incident terahertz wave for pre-selection. A second focusing lens is configured between the second polarizer and the terahertz wave detection end to focus the terahertz wave for detection.

7. A terahertz spectral quantum weak measurement system according to claim 5, characterized in that, The sample carrier is a sample cell or a prism coated with a metal grating.

8. The application of a terahertz spectroscopy quantum weak measurement system according to any one of claims 5-7 in the highly sensitive detection of chiral drugs.

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